Others have described devices for the handling and/or removal of cerebrospinal fluid (CSF) to and from a patient.
For example, several patents disclose various methods for diverting or shunting CSF from the CSF space (ventricle, spinal column) to another portion of the body (e.g., abdomen, peritoneal cavity). See, e.g., U.S. Pat. Nos. 2,969,066; 3,889,687; 6,575,928 and 7,118,549. Others have described administering therapeutic agents to the CSF space, but do not disclose removing the CSF. See, e.g., U.S. Pat. Nos. 5,531,673; 6,056,725; 6,594,880; 6,682,508 and 6,689,756. Generally, the therapeutic agents are locally delivered to the brain but not to the greater cerebrospinal fluid space, which includes the brain and the spine. Others disclose removing CSF, but generally do not administer therapeutic agent or any other fluid. See, e.g.; U.S. Pat. Nos. 3,889,687; 5,683,357; 5,405,316 and 7,252,659.
Devices exist having both input and output catheters for administering therapeutic agents or synthetic CSF and removing endogenous CSF, but the close spatial placement of the inflow and outflow catheters do not allow for flow of CSF throughout the cerebrospinal fluid space or full CSF exchange that provides access to the complete intracranial and intraspinal CSF volume. See, e.g., U.S. Pat. Nos. 4,378,797; 4,904,237; 6,537,241 and 6,709,426.
Furthermore, publications disclosing the exchange of CSF describe replacing endogenous CSF with synthetic CSF replacement fluid. See, e.g., U.S. Patent Publication No. 2003/0065309; and PCT Publication Nos. WO 01/154766 and WO 03/015710. In this way, the concentration of the toxic species may be diluted but not removed. It has been proposed to treat drug overdose or removal of tumor cells to clear debris before implantation of a ventriculo-peritoneal shunt shunt system. Such an apparatus is unnatural in that it requires flushing the entire system with an artificially produced solution rather than removing the toxins of interest from the patient's endogenous CSF, requires liters of instilled replacement fluid to be delivered on a regular basis, is neither targeted nor focused for removal of specific toxins of interest and is only practical in an acute setting where liters of fluid could be instilled. See, e.g. PCT Publication No. WO 01/54766.
Various devices aimed at accessing the CSF or indirectly targeting the nervous system exist, however there exists no CSF purification system that allows for the direct, targeted, logical and disease-specific removal of one or more of target compounds or the use of a dual or multi-lumen catheter that influences or controls CSF flow, mixing and efficiency of turnover.
It is desirable to provide a method and system for processing and removal of one or more target compounds from the CSF of a patient. Recently, a treatment for Alzheimer's disease was suggested which relied on removal of CSF by diversion of the fluid from the brain (ventricular system) to another portion of the patients body (e.g. abdomen/peritoneal cavity) using a modified ventriculo-peritoneal shunt system. See, e.g., U.S. Pat. Nos. 5,980,480 and 7,025,742. By continuously draining CSF at a low rate, the rationale was that the body's daily production of new CSF would dilute the concentration of contaminating substances remaining in the endogenous CSF. Such a system has several inherent limitations. The rate at which the concentration of toxic species is lowered is mediated by passive flow, is very slow, addresses only a fraction (milliliters) of the total CSF volume per hour, is not targeted or focused in removing specific items of interest and does not prevent reabsorption of toxic species back into the systemic circulation and thereby back into the CSF. See, e.g. U.S. Pat. Nos. 5,980,480; 6,264,625; 6,689,085.
The present invention addresses this and other needs.